This invention relates to a system for controlling the release of fuel vapors into the atmosphere from the fuel filler pipe of a vehicle's fuel tank.
As currently designed, vehicle fuel tanks normally operate under a positive pressure. Accordingly, when the filler cap for such a tank is removed, fuel vapors are released into the atmosphere. Similarly, as the tank is filled with fuel, fuel vapors in the tank are forced out of the tank into the atmosphere by the incoming fuel. The release of fuel vapors into the atmosphere under these conditions is undesirable for both environmental and health reasons.
The present invention is directed to controlling the release of fuel vapors into the atmosphere under the foregoing conditions. Specifically, rather than allowing the vapors to escape, the invention routes them to a vehicle-mounted, vapor capture device, such as, a charcoal canister, from which the vapors can be later removed and safely burned in the vehicle's engine.
In addition to controlling vapor escape, the invention also prevents liquid fuel from flowing into the vapor capture device during filling of the fuel tank. Moreover, the invention provides automatic relief for over pressure conditions within the vehicle's fuel tank, is easy to construct, reliable, crash-worthy, and can be readily installed in place of conventional filler pipe assemblies.